Between May 1946 and November 1948 the 28 main Japanese war leaders, with the exception of the emperor, were tried by the Tokyo Tribunal, formally the International Military Tribunal for the Far East. These were so-called class A war criminals who were charged with crimes against peace. In addition, there were local trials in the various allied areas of some 4,000 Japanese war criminals of the B and C categories: perpetrators of conventional war crimes and crimes against humanity.

After the war there were still about 300,000 Japanese in the Dutch East Indies. In May, June and July 1946 more than 90% of them were transported to Japan. Approximately 13,000 Japanese stayed behind to do coolie work for the Dutch East Indies government; early May 1947 the last Japanese coolies left the Dutch East Indies. An unknown number of Japanese deserters (no more than a few thousand) stayed behind. A small percentage of them provided military support to the Indonesian independence fighters for ideological reasons. More than 3,000 Japanese remained in the Dutch East Indies because they were suspected of having committed war crimes. Almost half of this group were repatriated together with the Japanese coolies in the first half of 1947. Some of the suspects were taken to Singapore to be tried there.

Eventually more than 1,000 Japanese and 43 Korean and Formosan camp guards were tried in the Dutch East Indies. During the war the allies had already started gathering evidence. Furthermore, in the final months of 1945 and the first half of 1946 various investigation services recorded thousands of statements by victims and witnesses of Japanese war crimes in and outside the Dutch East Indies (for example on board repatriation ships). The preliminary investigation of war crimes did not have to meet the safeguards of normal criminal law, and the rules of evidence were substantially relaxed for the courts-martial.

Twelve Temporary Courts Martial were installed to try the accused. The Japanese who had to appear before these court-martials were defended by Japanese-speaking lawyers, who, if necessary, were brought in from Japan. They were assisted by Japanese who were knowledgeable about the local situation and who had a command of Dutch, English, or Indonesian. However, communication remained a problem and nearly all the statements had to be translated by interpreters. The lawyers had a lot of work to do, but they did not always have access to the facilities they deemed necessary to do it. There even were instances where detained suspects were mistreated by their guards – often Europeans who had been held captive by the Japanese during the war.

In August 1946 the first trial took place before the Temporary Court Martial in Batavia. The last sentence was pronounced in June 1949. The Temporary Courts-Martial on Java and Sumatra focused mainly on war crimes against the European population of these islands, the courts-martial on Borneo and in the East – where there had been almost no Europeans outside the camps – focused largely on crimes against the Indonesian population.

More than 1,000 Japanese were tried; 55 of them (more than 5%) were acquitted and 983 convicted. Almost one quarter of the convicted Japanese received a death sentence. It appears that the Temporary Courts Martial judged relatively harshly. In the Dutch East Indies, for example, 236 Japanese were sentenced to death, as compared to 13 Germans in the Netherlands. Furthermore, these 13 Germans were reprieved, whereas in the Dutch East Indies only ten people were granted a reprieve.

The Dutch East Indian Temporary Courts Martial furthermore arrived at relatively fewer acquittals than other allied judiciary bodies that judged accused Japanese. The strictness of the East Indian courts-martial possibly resulted in the suicide of several Japanese accused. In addition, some 20 detained Japanese attempted to escape: about half of them managed to get away, six died in the attempt.

When negotiations on the transfer of sovereignty started between the Netherlands and the Republic of Indonesia in the second half of 1949, the question in official circles in the Dutch East Indies was what to do with the hundreds of Japanese criminals of war who still had to serve their sentence in the Tjipinang prison in Batavia. In various petitions for clemency Japanese relatives requested permission to have the convicted Japanese repatriated to Japan to finish their sentence there.

A Red Cross representative in The Hague volunteered the assistance of his organization to transport the condemned Japanese from Batavia to Tokyo. This offer was accepted. On 26 December 1949, one day before the transfer of sovereignty, the ‘Tjisedane’ left Batavia with 680 Japanese war criminal on board. The transport was supervised by the Red Cross.

On 23 January 1950 the ship arrived at Yokohama. The Japanese who had been given a prison sentence by the East-Indian courts martial, were taken to the Sugamo-prison in Tokyo to serve the remainder of their sentence. In the summer of 1956 the Netherlands paroled the last of the Japanese war criminals sentenced in the East Indies. Finally, in December 1958, the conditions for early release were also withdrawn.